KR20200130258A - Light-emitting element, light source device and projector - Google Patents

Abstract

An object of the present invention is to provide a light-emitting device capable of further suppressing the spread of a light-emitting region and further improving directivity. At least a phosphor layer 1002 and an emission angle selection layer 1001 for emitting light incident at a predetermined angle, and the phosphor layer 1002 includes a phosphor 500 and a light scattering material 600, A light emitting device in which the phosphor layer 1002 and the light emission angle selection layer 1001 are arranged in this order is provided.

Description

Light-emitting element, light source device and projector

The present technology relates to a light-emitting element, a light source device, and a projector.

BACKGROUND ART Recently, in optical devices such as lighting fixtures, displays, projectors, and the like, there is a demand for efficiently emitting light in a direction required for various applications.

For example, a plurality of nanostructures formed of metal and formed in a two-dimensional periodic arrangement, and a wavelength conversion layer emitting light having a wavelength different from that of excitation light, and in the nanostructure, excitation light Optical devices having different lengths in a predetermined first direction parallel to the incident surface (e.g., long side length) and in a second direction parallel to the incident surface and perpendicular to the first direction (short side length) Has been proposed (refer to Patent Document 1).

In addition, for example, it has a photoluminescent layer, a light-transmitting layer, and a periodic structure, and the periodic structure includes at least one of a plurality of convex portions and a plurality of concave portions, and the photoluminescent layer The light emitted by the necessity layer includes first light having _a wavelength of λ _a in the air, and a distance between adjacent convex portions or concave portions is D _int , and the photoluminescence of the first light When the refractive index of the layer is n _{wav -a} , the relationship of λ _a / n _{wav -a} <D _int <λ _a is established, and the spectrum of light emitted in a direction perpendicular to the photoluminescence layer through the periodic structure A light emitting device has been proposed in which the wavelength A at which the intensity peaks in is deviated from the wavelength B at which the intensity peaks in the emission spectrum of the photoluminescence material included in the photoluminescence layer (Patent Document 2).

Further, for example, a phosphor layer generating fluorescence by incident light, and a plasmon excitation layer that excites a first surface plasmon by the fluorescence are sequentially stacked, and the phosphor layer in the plasmon excitation layer The first surface plasmon or light generated on the opposite side of the surface in contact with the surface has an emission part for extracting it as emission light, and the phosphor layer has metal fine particles that excite the second surface plasmon by the incident light, An optical element has been proposed (refer to Patent Document 3).

Patent Document 1: Japanese Patent Laid-Open No. 2017-157488 Patent Document 2: Japanese Patent Laid-Open No. 2016-171228 Patent Document 3: International Publication No. 2012/049905

However, in the techniques proposed in Patent Documents 1 to 3, it may be difficult to further suppress the spread of the light emitting region or to further improve the directivity.

Accordingly, the present technology has been made in view of such a situation, and it is mainly to provide a light-emitting element capable of further suppressing the spread of the light-emitting area and further improving directivity, and a light source device and a projector including the light-emitting element. The purpose.

The inventors of the present invention, as a result of careful research in order to solve the above-described object, surprisingly, succeeded in further suppressing the spread of the light-emitting region and further improving the directivity, and came to complete the present technology.

That is, in the present technology, first, a phosphor layer and an emission angle selection layer for emitting light incident at a predetermined angle are provided, the phosphor layer includes a phosphor and a light scattering material, and the phosphor layer and the emission angle It provides a light-emitting device in which the selection layers are arranged in this order.

The light emitting device according to the present technology further includes a reflective layer,

In the light emitting device according to the present technology, the reflective layer, the phosphor layer, and the emission angle selection layer may be arranged in this order.

The light-emitting device according to the present technology further includes a dielectric spacer,

In the light emitting device according to the present technology, the dielectric spacer may be disposed between the reflective layer and the phosphor layer, and further, the dielectric spacer has a dielectric constant of 2.5 to 6.0 in a region of a wavelength of 380 nm to 780 nm. And may have a thickness of 10 nm to 400 nm.

In the light emitting device according to the present technology, the phosphor layer further comprises metal nanoparticles,

The metal nanoparticles may be disposed on the surface of the phosphor.

The light emitting device according to the present technology further includes a reflective layer, the reflective layer, the phosphor layer, and the emission angle selection layer are arranged in this order, the phosphor layer further comprises metal nanoparticles, and the metal nanoparticles Particles may be disposed on the surface of the phosphor.

The light emitting device according to the present technology further includes a reflective layer and a dielectric spacer,

The reflective layer, the dielectric spacer, the phosphor layer, and the emission angle selection layer may be arranged in this order,

The phosphor layer further includes metal nanoparticles, and the metal nanoparticles may be disposed on the surface of the phosphor, and further, the dielectric spacer has a dielectric constant of 2.5 to 6.0 in a region of a wavelength of 380 nm to 780 nm, It may have a thickness of 10 nm to 400 nm.

In the light emitting device according to the present technology, the phosphor may be a low reabsorption phosphor.

In the light emitting device according to the present technology, the emission angle selection layer may be formed of a dielectric film.

In the light emitting device according to the present technology, the emission angle selection layer may have a grating structure or a patch structure.

In the light-emitting device according to the present technology, the light-scattering reflector may be a light-scattering reflector, a scattering particle, or a void.

In addition, the present technology provides a light source device comprising a light-emitting element according to the present technology, a light source for emitting excitation light, and a movement mechanism for moving the irradiation position of the excitation light to the light-emitting element over time. .

Further, in the present technology, a light source device according to the present technology, an image generation unit that generates an image using light emitted from the light source device, and a projection unit that projects an image generated by the image generation unit are provided. To provide a projector.

According to the present technology, spreading of the light emitting region can be further suppressed and directivity can be further improved. In addition, the effect described herein is not necessarily limited, and any effect described in the present disclosure may be used.

1 is a cross-sectional view showing a configuration example of a light emitting device according to a first embodiment to which the present technology is applied.
2 is a graph showing an example of the relationship between the absorption spectrum and the emission spectrum of a phosphor.
3 is a graph showing an example of the relationship between the absorption spectrum and the emission spectrum of a phosphor.
4 is a cross-sectional view showing a configuration example of a light emitting device according to a second embodiment to which the present technology is applied.
5 is a cross-sectional view showing a configuration example of a light emitting device according to a third embodiment to which the present technology is applied.
6 is a cross-sectional view showing a configuration example of a light emitting element according to a fourth embodiment to which the present technology is applied.
Fig. 7 is a plan view of the light emitting element of the fourth embodiment to which the present technology is applied, as viewed from above.
8 is a cross-sectional view showing a configuration example of a light emitting element according to a fifth embodiment to which the present technology is applied.
Fig. 9 is a plan view of a light emitting device according to a fifth embodiment to which the present technology is applied, as viewed from above.
10 is a cross-sectional view showing a configuration example of a light emitting element according to a sixth embodiment to which the present technology is applied.
11 is a graph showing the dependence of the concentration of the TiO ₂ scattering particles on the diameter of the emission spot.
12 is a graph showing the dependence of the emission angle of the emission light on the critical angle of the dielectric film.
13 is a perspective view showing a configuration example of a light source device according to a seventh embodiment to which the present technology is applied.
14 is a plan view of a light source device according to a seventh embodiment to which the present technology is applied, as viewed from above.
15 is a schematic diagram showing a configuration example of a projector according to an eighth embodiment to which the present technology is applied.

Hereinafter, preferred embodiments for implementing the present technology will be described. The embodiment described below shows an example of a typical embodiment of the present technology, and thus the scope of the present disclosure should not be construed narrowly. In the meantime, in the description using the drawings, the same or equivalent elements or members are denoted by the same reference numerals, and duplicate descriptions are omitted.

In addition, explanation is performed in the following order.

1. Overview of this technology

2. First Embodiment (Example 1 of light-emitting element)

3. Second Embodiment (Example 2 of light-emitting element)

4. Third Embodiment (Example 3 of light-emitting element)

5. Fourth Embodiment (Example 4 of light-emitting element)

6. Fifth Embodiment (Example 5 of light-emitting element)

7. Sixth embodiment (Example 6 of light-emitting element)

8. Seventh embodiment (example of light source device)

9. Embodiment 8 (example of projector)

<1. Overview of this technology>

First, an overview of this technology will be described.

The present technology relates to a light-emitting element, a light source device, and a projector.

In the phosphor light source, the coupling efficiency between the light source and the optical system coupled thereto may decrease due to the spread of the light emitting region inside the phosphor layer and the divergence angle of the emitted fluorescence. In the phosphor light source, there is an example of suppressing the divergence angle of emitted fluorescence by using a diffractive structure, but there is a limitation that only the divergence angles within one or two vertical planes with respect to the emission surface can be controlled. However, in this example, a countermeasure to suppress spreading of the light-emitting region is not applied. In addition, there is an example in which fluorescence emission is enhanced by surface plasmon phenomenon of metal nanoparticles and a bulk medium. However, since the metal nanoparticles and the bulk medium are not used in an environment in which excitation light is multiplely reflected, the excitation efficiency is still low.

The present technology can reduce etendue (= size of light-emitting region x emission divergence angle). Furthermore, the present technology can minimize the reduction in the amount of light emission.

Etendu can be reduced by combining the following techniques A and B.

A. The scattering structure suppresses the spread of the fluorescent light emitting region in the phosphor layer (suppressing the spread of the light emitting region),

B. The emission angle-dependent emission angle selection layer (e.g., dielectric film) allows only fluorescence with a small emission angle to be emitted, and the fluorescence incident from the phosphor layer side to the emission angle selection layer (dielectric film) at an angle greater than the critical angle Is reflected and repeats scattering inside the layer until it is incident at an angle less than the critical angle (improved directivity),

In addition, since fluorescence is multiplely reflected inside the phosphor layer, the amount of fluorescence emission decreases due to the reabsorption of the phosphor, and the phosphor temperature may increase. In order to improve the decrease in the amount of fluorescence emission and the increase in the temperature of the phosphor, the fluorescence emission characteristics and temperature characteristics can be improved by the following C technique.

C. Use a phosphor with a low reabsorption rate (improvement of light emission attenuation by phosphor reabsorption).

Further, according to the present technology, when the phosphor layer is formed on a circular substrate and is rotated and used, the temperature of a portion irradiated with excitation light (excitation light irradiation unit) can be temporally relaxed to improve heat dissipation performance.

This technology reduces etendue (= size of light-emitting area × emission angle) and further reduces the amount of light emission to a minimum, so it is possible to minimize the light source for projectors, transmission type spatial modulation panels, spot lighting, automobile headlights, and windows. It can be preferably applied to the like.

<2. First Embodiment (Example 1 of light-emitting element)>

The light-emitting element of the first embodiment (light-emitting element example 1) according to the present technology includes at least a phosphor layer and an emission angle selection layer that emits light incident at a predetermined angle, and the phosphor layer is a phosphor and light scattering. It is a light-emitting element including a body, and the phosphor layer and the light emission angle selection layer are arranged in this order. Here, the light incident at a predetermined angle means that the light enters the emission angle selection layer from the phosphor layer side through the surface of the phosphor layer below a critical angle. On the other hand, when light is incident on the emission angle selection layer below the critical angle, the emission angle selection layer emits light, and when light is incident on the emission angle selection layer at an angle greater than the critical angle, the emission angle selection layer is at an angle below the critical angle. Light is scattered repeatedly inside the phosphor layer until light is incident on it.

The light emitting element of the first embodiment according to the present technology may further include a reflective layer. In this case, the light emitting element of the first embodiment according to the present technology includes a reflective layer, the phosphor layer, and a light exit angle selection layer. These are arranged in this order.

According to the light emitting device of the first embodiment according to the present technology, etendue can be reduced. Further, as will be described later, in the case where a low reabsorption phosphor is used for the phosphor layer, the light emitting device of the first embodiment according to the present technology can further improve light emission attenuation.

In Fig. 1, a light-emitting element 1000 (a light-emitting element 1000-1 in Fig. 1), which is an example of a light-emitting element according to a first embodiment according to the present technology, is shown. 1 is a cross-sectional view of a light emitting device 1000-1.

The light-emitting element 1000-1 includes a phosphor layer 1002, an emission angle selection layer 1001, and a reflection layer 1003, and a reflection layer 1003, a phosphor layer 1002, and an emission angle selection layer (1001) is arranged in this order. As shown in FIG. 1, the surface of the light emitting element 1000-1 on the side of the incident light (excitation light B1 and B2) and the emission light (fluorescence light emission A1 and A2) becomes the emission angle selection layer 1001. The phosphor layer 1002 includes a phosphor 500 and a light scattering material 600. The emission angle C of the emission light (fluorescent light emission A1 and A2) can be made small by the emission angle selection layer 1001.

In the light emitting element 1000-1, the phosphor layer 1002 is held so as to have an arbitrary thickness on the reflective layer 1003 (e.g., a mirror substrate), and incident light (excitation light B1 and The emission angle selection layer 1001 is disposed on the surface of B2) and the emission light (fluorescent light emission A1 and A2) side. The emission angle selection layer 1001 is not particularly limited, but may be formed of a dielectric film (for example, a thin multilayer film made of a dielectric material).

The phosphor 500 may contain, for example, at least one material selected from organic materials, inorganic materials, YAG-based, ZnS, ZnSe, CdS, and CdSe as a constituent material. The phosphor 500 is preferably made of a low reabsorption phosphor. By being composed of a low reabsorption phosphor, light emission attenuation can be improved. The light emission half width of the phosphor 500 is not particularly limited, but may be 130 nm or less. Further, the phosphor 500 is, for example, phosphor particles. In the case of phosphor particles, for example, when it is a quantum dot, the average particle diameter is not particularly limited, but it is preferably 2 nm to 10 nm, and in the case of a Ce:YAG phosphor, the average particle diameter is not particularly limited, It is preferably 1 to 50 µm. The concentration of the phosphor 500 (for example, phosphor particles) in the phosphor layer 1002 is also not particularly limited. For example, in the case of quantum dots, the concentration is preferably 2 to 34 Vol%, for example, Ce : In the case of a YAG phosphor, the concentration is preferably 40 to 70 Vol%.

The light scattering body 600 may be a scattering particle, and the scattering particles may be made of at least one material of silica-based and oxide as a constituent material, and the light scattering body 600 (e.g., scattering particles) in the phosphor layer 1002 The concentration of) is not particularly limited, but is preferably 0.5 Vol% or more. In addition, the light scattering body 600 may be a void. The light scattering body 600 can suppress the spread of the fluorescent emission region in the phosphor layer 1002.

The reflective layer 1003 may be a mirror substrate, or may be made of at least one of a dielectric material and a metal material as a constituent material, and it is preferable that the reflectance in the wavelength range of 380 to 780 nm is 80% or more. The overlapping ratio of the absorption spectrum and the emission spectrum is not particularly limited, but a small overlapping ratio is preferable, and for example, the overlapping ratio may be 10% or less.

In Fig. 2, the relationship between the absorption spectrum and the emission spectrum of the phosphor is shown. In the graph of Fig. 2, the vertical axis represents absorption rate (Absorptance) (a vertical axis indicated by arrow P2 in Fig. 2) and fluorescence emission intensity (a vertical axis indicated by arrow Q2 in Fig. 2), and the horizontal axis Is the wavelength. Referring to FIG. 2, it is possible to confirm the existence of a wavelength region in which the absorption spectrum and the emission spectrum overlap, and that the absorption rate in the emission wavelength region is high.

3 shows the relationship between the absorption spectrum and the emission spectrum of the low reabsorption phosphor. In the graph of Fig. 3, the vertical axis indicates the absorption rate (the vertical axis indicated by the arrow P3 in Fig. 3) and the fluorescence emission intensity (the vertical axis indicated by the arrow Q3 in Fig. 3), and the horizontal axis indicates the wavelength. Referring to Fig. 3, it can be seen that there is almost no presence in the wavelength region where the absorption spectrum and the emission spectrum overlap, and it can be seen that the absorption rate in the emission wavelength region is low.

Fig. 11 shows a graph of the result of optical simulation 1 of the fluorescence spot diameter with respect to the volume concentration of the scattering particles (TiO ₂ ) having a particle diameter of 1.0 μm causing Mie scattering. On the other hand, in the optical simulation 1, scattering particles having a particle diameter of 1.0 μm were used, but the particle diameter of the scattering particles is not particularly limited as long as it is a scale that causes Mie scattering. In the graph of Fig. 11, the vertical axis represents the diameter of a light emission spot (mm), and the horizontal axis represents the TiO ₂ concentration (vol%) (TiO ₂ concentration).

Hereinafter, the content of optical simulation 1 will be described in detail.

(purpose)

The influence of the concentration of TiO ₂ particles contained in the phosphor layer on the size of the light emitting region was confirmed.

(Calculation method)

The concentration of the TiO ₂ particles inside the phosphor was changed, and the diameter of the light emitting circular region on the surface of the phosphor layer was calculated.

(result)

It was confirmed that the higher the TiO ₂ particle concentration, the smaller the emission size. That is, when the concentration is 0.5 Vol% or more, the size of the light emission spot becomes small, and the diameter of the spot becomes φ 1.32 mm. It was confirmed that 10% reduction in the size of the light emission spot was possible compared to the state in which the scattering particles were not added.

Further, Fig. 12 shows the results of optical simulation 2 of the critical angle dependence of the dielectric film (emission angle selection layer) of the fluorescence emission light. In optical simulation 2, the TiO ₂ scattering particles were calculated by setting the diameter of 1.0 µm and the volume concentration to 0.5 Vol%. The vertical axis is the beam divergence angle (degrees), and the horizontal axis is the angle which can emission (degrees).

Hereinafter, the content of optical simulation 2 will be described in detail.

(purpose)

The influence of the emission critical angle of the dielectric multilayer film (the emission angle selection layer) on the emission divergence angle was confirmed.

(Calculation method)

The angle incident on the dielectric multilayer film from the phosphor layer side is set to θ. A restriction was set in that only when incident on the dielectric film from the phosphor layer side at an angle smaller than θ is transmitted through the dielectric film and fluorescence is emitted. The divergence angle when θ was changed to 20 degrees, 30 degrees, and 40 degrees was calculated.

(result)

It was confirmed that the fluorescence divergence angle became the smallest when θ was 20 degrees. By reducing the critical angle of the dielectric multilayer film from 40 degrees to 20 degrees, it has become possible to reduce the emission angle from 74 degrees to 12 degrees. On the other hand, based on the result of optical simulation 2, it is considered that the directivity increases more toward a region smaller than 20 degrees.

<3. Second Embodiment (Example 2 of Light-Emitting Element)>

The light-emitting element of the second embodiment (Example 2 of the light-emitting element) according to the present technology includes at least a phosphor layer, an emission angle selection layer for emitting light incident at a predetermined angle, a reflective layer, and a dielectric spacer. , The phosphor layer includes a phosphor and a light scattering material, and a reflective layer, a dielectric spacer, a phosphor layer, and a light emission angle selection layer are arranged in this order.

In the light emitting device of the second embodiment according to the present technology, the dielectric spacer may have an arbitrary dielectric constant and thickness in an arbitrary wavelength range, but a dielectric constant of 2.5 to 6.0 in a wavelength range of 380 nm to 780 nm. And preferably having a thickness of 10 nm to 400 nm.

According to the light emitting device of the second embodiment according to the present technology, etendue can be reduced. Further, as will be described later, in the case where a low reabsorption phosphor is used for the phosphor layer, the light-emitting attenuation of the light-emitting element of the second embodiment according to the present technology can be further improved.

Fig. 4 shows a light-emitting element 1000 (a light-emitting element 1000-4 in Fig. 4), which is an example of a light-emitting element according to a second embodiment according to the present technology. 4 is a cross-sectional view of the light-emitting device 1000-4.

The light emitting element 1000-4 includes a phosphor layer 1002, an emission angle selection layer 1001, a dielectric spacer 1004 and a reflective layer 1003, a reflective layer 1003, and a dielectric spacer 1004. Wow, the phosphor layer 1002 and the emission angle selection layer 1001 are arranged in this order. The surface of the light-emitting element 1000-4 on the side of the incident light (not shown in FIG. 4, but excitation light) and the outgoing light (not shown in FIG. 4, but fluorescent light emission) becomes an emission angle selection layer 1001. The phosphor layer 1002 includes a phosphor 500 and a light scattering material 600.

As described above, the light emitting element 1000-4 has a structure in which a dielectric spacer 1004 is disposed between the phosphor layer 1002 and the reflective layer (mirror substrate) 1003. In this case, the mirror substrate 1003 uses a metal mirror, and surface plasmons are excited on the metal surface by excitation light or fluorescence. The excited surface plasmon may generate a strong electric field to excite the phosphor 500 and increase the amount of fluorescence emission. For example, from the viewpoint of the refractive index of the transparent oxide, the dielectric spacer 1004 may be a material having a dielectric constant of 2.5 to 6.0 in a range of 380 nm to 780 nm. The thickness of the dielectric spacer 1004 may be in the range of 10 nm to 400 nm, for example, from the viewpoint of the dielectric constant of the dielectric spacer and the electric field penetration depth generated by surface plasmons in the air medium. When the dielectric constant and thickness are specified as described above, the excitation efficiency of the phosphor by surface plasmon becomes more favorable.

With respect to the light-emitting element of the second embodiment related to the present technology, other than the contents described above, the content described in the column of the light-emitting element of the first embodiment related to the present technology is the light-emitting element of the second embodiment related to the present technology. It can be applied as is.

<4. 3rd Embodiment (Example 3 of light-emitting element)>

The light-emitting element of the third embodiment (Example 3 of the light-emitting element) according to the present technology includes at least a phosphor layer and an emission angle selection layer for emitting light incident at a predetermined angle, and the phosphor layer is a phosphor and light scattering. It is a light-emitting device including a body and metal nanoparticles, metal nanoparticles are disposed on a surface of a phosphor, and a phosphor layer and a light emission angle selection layer are disposed in this order.

The light emitting device of the third embodiment according to the present technology may further include a reflective layer, and in this case, the light emitting device of the third embodiment according to the present technology includes a reflective layer, a phosphor layer, and a light emission angle selection layer. , Are arranged in this order. In addition, the light-emitting element of the third embodiment according to the present technology may further include a reflective layer and a dielectric spacer. In this case, the reflective layer, the dielectric spacer, the phosphor layer, and the light emission angle selection layer are They are placed in order.

When the light emitting element of the third embodiment according to the present technology includes a dielectric spacer, the dielectric spacer may have an arbitrary dielectric constant and thickness in an arbitrary wavelength range, but in a range of 380 nm to 780 nm in wavelength, It has a dielectric constant of 2.5 to 6.0, and preferably has a thickness of 10 nm to 400 nm.

According to the light emitting device of the third embodiment according to the present technology, etendue can be reduced. Further, as will be described later, in the case where a low reabsorption phosphor is used for the phosphor layer, the light emitting device of the third embodiment according to the present technology can further improve light emission attenuation.

In Fig. 5, a light-emitting element 1000 (a light-emitting element 1000-5 in Fig. 5) which is an example of a light-emitting element according to a third embodiment according to the present technology is shown. 5 is a cross-sectional view of the light emitting device 1000-5.

The light-emitting element 1000-5 includes a phosphor layer 1002, an emission angle selection layer 1001, and a reflection layer 1003, and a reflection layer 1003, a phosphor layer 1002, and an emission angle selection layer ( 1001) are arranged in this order. The surface of the light-emitting element 1000-5 on the side of the incident light (not shown in FIG. 5, but excitation light) and the outgoing light (not shown in FIG. 5, but fluorescent light emission) becomes the emission angle selection layer 1001. The phosphor layer 1002 includes a phosphor 500 and a light scattering material 600. As shown in FIG. 5, metal nanoparticles 700 are disposed on the surface of the phosphor 500.

As described above, the light-emitting element 1000-5 has a structure in which metal nanoparticles 700 are disposed on the surface of the phosphor 500. Surface plasmons are excited on the surface of the metal nanoparticles 700 by excitation light or fluorescence, and the electric field becomes localized. The phosphor can be excited not only by excitation light but also by a localized strong electric field, and the amount of fluorescence emission can be enhanced. Since there is multiple reflection of light between the dielectric film (emission angle selection layer 1001) and the mirror (reflection layer 1003), plasmons can be efficiently excited. Although the metal nanoparticles may have an arbitrary average particle diameter, it is preferable to have an average particle diameter of 200 nm or less, and at least one metal of Au, Ag, and Ti may be used as a constituent material. The distance between the metal nanoparticle 700 and the phosphor 500 is not particularly limited, but is preferably 20 nm or less.

With respect to the light-emitting element of the third embodiment related to the present technology, other than the contents described above, the content described in the column of the light-emitting element of the first embodiment related to the present technology is the light-emitting element of the third embodiment related to the present technology. It can be applied as is.

<5. 4th Embodiment (Example 4 of light-emitting element)>

The light-emitting element of the fourth embodiment (Example 4 of the light-emitting element) according to the present technology includes at least a phosphor layer and an emission angle selection layer for emitting light incident at a predetermined angle, and the phosphor layer is a phosphor and light scattering. It is a light emitting device including a body, the phosphor layer and the light emission angle selection layer are arranged in this order, and the emission angle selection layer has a lattice structure.

The light emitting element of the fourth embodiment according to the present technology may further include a reflective layer. In this case, the light emitting element of the fourth embodiment according to the present technology includes a reflective layer, a phosphor layer, and a light exit angle selection layer. , Are arranged in this order. In addition, the light emitting element of the fourth embodiment according to the present technology may further include a reflective layer and a dielectric spacer. In this case, the reflective layer, the dielectric spacer, the phosphor layer, and the light emission angle selection layer are They are placed in order.

When the light emitting element of the fourth embodiment according to the present technology includes a dielectric spacer, the dielectric spacer may have an arbitrary dielectric constant and thickness in an arbitrary wavelength range, but in a range of 380 nm to 780 nm in wavelength, It has a dielectric constant of 2.5 to 6.0, and preferably has a thickness of 10 nm to 400 nm.

According to the light emitting device of the fourth embodiment according to the present technology, etendue can be reduced. Further, as will be described later, in the case where a low reabsorption phosphor is used for the phosphor layer, the light emitting device of the fourth embodiment according to the present technology can further improve light emission attenuation.

6 shows a light-emitting element 1000 (a light-emitting element 1000-6 in FIG. 6), which is an example of a light-emitting element according to the fourth embodiment according to the present technology. 6 is a cross-sectional view of the light emitting device 1000-6. 7 is a plan view of the light-emitting element 1000-6 viewed from above.

The light-emitting element 1000-6 includes a phosphor layer 1002, an emission angle selection layer 1006, and a reflection layer 1003, and a reflection layer 1003, a phosphor layer 1002, and an emission angle selection layer (1006) is arranged in this order. The surface of the light-emitting element 1000-6 on the side of incident light (not shown in FIG. 6, but excitation light) and outgoing light (not shown in FIG. 6, but fluorescent light emission) becomes an emission angle selection layer 1006. The phosphor layer 1002 includes a phosphor 500 and a light scattering material 600. As shown in Fig. 6, the emission angle selection layer 1006 has a lattice structure.

The lattice structure will be described in more detail with reference to FIG. 7. Referring to FIG. 7, the emission angle selection layer 1006 extends in a linear shape in the longitudinal direction of the light-emitting element 1000-6 (up-down direction in FIG. 7), and the transverse direction of the light-emitting element 1000-6 In (left-right direction in Fig. 7), pitches at substantially constant intervals are formed by the emission angle selection layer 1006 and the phosphor layer 1002.

An emission angle selection layer 1006 having a lattice structure is disposed on the surface of the phosphor layer 1002. Directivity can be improved by controlling the diffraction wavelength and diffraction direction according to the material of the grating and the pitch interval. The material for constituting the emission angle selection layer 1006 having a grating (diffraction grating) is not particularly limited, but a material having a transmittance of 80% or more in a range of 380 to 780 nm is preferable.

With respect to the light-emitting element of the fourth embodiment related to the present technology, other than the contents described above, the content described in the column of the light-emitting element of the first embodiment related to the present technology is the light-emitting element of the fourth embodiment related to the present technology. It can be applied as is.

<6. Fifth Embodiment (Example 5 of light-emitting element)>

The light-emitting element of the fifth embodiment (Example 5 of the light-emitting element) according to the present technology includes at least a phosphor layer and an emission angle selection layer for emitting light incident at a predetermined angle, and the phosphor layer is a phosphor and light scattering. A light-emitting device including a body, a phosphor layer and a light emission angle selection layer are arranged in this order, and the emission angle selection layer has a patch structure.

The light-emitting element of the fifth embodiment according to the present technology may further include a reflective layer. In this case, the light-emitting element of the fifth embodiment according to the present technology includes a reflective layer, a phosphor layer, and a light emission angle selection layer. , Are arranged in this order. In addition, the light emitting device of the fifth embodiment according to the present technology may further include a reflective layer and a dielectric spacer. In this case, the reflective layer, the dielectric spacer, the phosphor layer, and the light emission angle selection layer are They are placed in order.

When the light emitting element of the fifth embodiment according to the present technology includes a dielectric spacer, the dielectric spacer may have an arbitrary dielectric constant and thickness in an arbitrary wavelength range, but in a range of 380 nm to 780 nm in wavelength, It has a dielectric constant of 2.5 to 6.0, and preferably has a thickness of 10 nm to 400 nm.

According to the light emitting device of the fifth embodiment according to the present technology, etendue can be reduced. Further, as described later, in the case where a low reabsorption phosphor is used for the phosphor layer, the light emitting device of the fifth embodiment according to the present technology can further improve light emission attenuation.

In Fig. 8, a light-emitting element 1000 (a light-emitting element 1000-8 in Fig. 8) which is an example of the light-emitting element of the fifth embodiment according to the present technology is shown. 8 is a cross-sectional view of the light-emitting device 1000-8. In addition, FIG. 8 is a plan view of the light emitting device 1000-8 viewed from above.

The light-emitting element 1000-8 includes a phosphor layer 1002, an emission angle selection layer 1007, and a reflection layer 1003, and a reflection layer 1003, a phosphor layer 1002, and an emission angle selection layer (1007) is arranged in this order. The surface of the light-emitting element 1000-8 on the side of the incident light (not shown in FIG. 8, but excitation light) and the outgoing light (not shown in FIG. 8, but fluorescent light emission) becomes an emission angle selection layer 1007. The phosphor layer 1002 includes a phosphor 500 and a light scattering material 600. As shown in Fig. 8, the emission angle selection layer 1007 has a patch structure.

Referring to Fig. 9, the patch structure will be described in more detail. Referring to FIG. 9, the emission angle selection layer 1007 is formed as a substantially circular patch on the surface of the phosphor layer 1002 in the vertical and horizontal directions (up and down directions and left and right directions in FIG. 9) at approximately regular intervals. Has been. The substantially circular patch may have a moth-eye structure.

Since the emission angle selection layer 1007 provided in the light emitting device 1000-8 has a patch structure (eg, a circular patch structure), directivity can be improved in a vertical plane in the entire direction with respect to the phosphor layer. .

With respect to the light-emitting element of the fifth embodiment related to the present technology, other than the contents described above, the content described in the column of the light-emitting element of the first embodiment related to the present technology is the light-emitting element of the fifth embodiment related to the present technology. It can be applied as is.

<7. 6th Embodiment (Example 6 of light-emitting element)>

The light-emitting element of the sixth embodiment (Example 6 of the light-emitting element) according to the present technology includes at least a phosphor layer and an emission angle selection layer for emitting light incident at a predetermined angle, and the phosphor layer is a phosphor and light scattering. A light-emitting element including a body, a phosphor layer and a light emission angle selection layer are arranged in this order, and the light scattering body is a light scattering reflector.

The light emitting device of the sixth embodiment according to the present technology may further include a reflective layer. In this case, the light emitting device of the sixth embodiment according to the present technology includes a reflective layer, a phosphor layer, and a light exit angle selection layer. , Are arranged in this order. In addition, the light emitting device of the sixth embodiment according to the present technology may further include a reflective layer and a dielectric spacer. In this case, the reflective layer, the dielectric spacer, the phosphor layer, and the light emission angle selection layer are They are placed in order.

When the light emitting element of the sixth embodiment according to the present technology includes a dielectric spacer, the dielectric spacer may have an arbitrary dielectric constant and thickness in an arbitrary wavelength range, but in a range of 380 nm to 780 nm in wavelength, It has a dielectric constant of 2.5 to 6.0, and preferably has a thickness of 10 nm to 400 nm.

According to the light emitting element of the sixth embodiment according to the present technology, etendue can be reduced. In addition, as will be described later, in the case where a low reabsorption phosphor is used for the phosphor layer, the light emitting device of the sixth embodiment according to the present technology can further improve light emission attenuation.

Fig. 10 shows a light-emitting element 1000 (a light-emitting element 1000-10 in Fig. 10) as an example of the light-emitting element according to the sixth embodiment according to the present technology. 10 is a cross-sectional view of the light emitting device 1000-10.

The light emitting element 1000-10 includes a phosphor layer 1002 and an emission angle selection layer 1001, and the phosphor layer 1002 and an emission angle selection layer 1001 are arranged in this order. The surface of the light-emitting element 1000-10 on the side of incident light (not shown in FIG. 10, but excitation light) and outgoing light (not shown in FIG. 10, but fluorescent light emission) becomes the emission angle selection layer 1001. The phosphor layer 1002 includes a phosphor 500 and a light scattering reflector 1005, which is a light scattering body. In Fig. 10, the light scattering reflector 1005 is from one side surface of the phosphor layer 1002 (for example, in Fig. 10, the left side of the phosphor layer 1002), and the bottom surface of the phosphor layer 1002 (Fig. In 10, through the lower portion of the phosphor layer 1002), the other side surface portion of the phosphor layer 1002 (for example, in FIG. 10, the right side portion of the phosphor layer 1002) is disposed.

In the light-emitting element 1000-10, a structure to which a reflector having high light scattering property is applied (light scattering reflector 1005) is used as a scattering structure. The reflector structure of the light scattering reflector 1005 at the bottom of the phosphor layer 1002 is formed by periodically or aperiodic processing of a microstructure. The light scattering reflector 1005 has an inclined structure on the inner wall surface of the phosphor layer 1002, and an effect that the fluorescence emission region is difficult to spread can be obtained. The constituent material of the light scattering reflector 1005 is not particularly limited, but it is preferably a solid material having a reflectance of 80% or more in a region of 380 to 780 nm in wavelength.

With respect to the light-emitting element of the sixth embodiment related to the present technology, other than the contents described above, the content described in the column of the light-emitting element of the first embodiment related to the present technology is the light-emitting element of the sixth embodiment of the present technology. It can be applied as is.

<8. 7th embodiment (example of light source device)>

The light source device of the seventh embodiment (example of the light source device) according to the present technology includes a light emitting element according to at least one of the first to sixth embodiments according to the present technology, a light source emitting excitation light, and And a moving mechanism for moving the irradiation position of the excitation light to the light emitting element over time.

13 is a perspective view showing a configuration example of a light source device according to a seventh embodiment according to the present technology. The light source device 100 is a light source for a projector, of a type for synthesizing a laser light in a blue wavelength region and light in a red wavelength region to a green wavelength region generated from a fluorescent substance excited by the laser light to emit white light. Device.

As shown in FIG. 13A, the light source device 100 includes a base 1 provided at the bottom and a side wall portion 2 fixed to the base 1. Further, the light source device 100 has a front portion 3 and an upper surface portion 4 connected to the side wall portion 2, and a cover portion 5 connected to the upper surface portion 4. The side wall portion 2, the front portion 3, the top portion 4, and the lid portion 5 constitute the housing portion 10 of the light source device 100.

The base 1 has an elongated shape in one direction. The long longitudinal direction in which the base 1 extends becomes the left-right direction of the light source device 100, and the short longitudinal direction orthogonal to the long longitudinal direction becomes the front-rear direction. Accordingly, one of the two long longitudinal portions facing in the short longitudinal direction becomes the front side 6 and the other becomes the rear side 7. In addition, a direction orthogonal to both the long length direction and the short length direction becomes the height direction of the light source device 100. In the example shown in FIG. 13, the x-axis, y-axis, and z-axis directions are the left-right direction, the front-rear direction, and the height direction, respectively.

13B is a view in which illustration of the front portion 3, the upper surface portion 4, and the lid portion 5 is omitted, and is a diagram illustrating an example of the internal configuration of the light source device 100. 13B, a notch 9 is formed in the center of the front side 6 in the side wall portion 2, and an opening 11 is formed in the rear side 7 have. In the notch 9 of the front side 6 of the side wall portion 2, a fluorescent optical unit 50 is disposed. The fluorescent optical unit 50 is fixed to the base 1 through a notch 9 so that the light emitting side faces the front side. Accordingly, the optical axis C of the light emitted from the fluorescent optical unit 50 extends in a direction parallel to the y-axis through approximately the center of the base 1 in plan view (see Fig. 14). On the other hand, the fluorescent optical unit 50 includes a light emitting element of at least one embodiment among the first to sixth embodiments according to the present technology.

Two condensing units 30 are arranged on the rear side 7 of the fluorescent optical unit 50. The condensing unit 30 is arranged with the optical axis C symmetrical. Each condensing unit 30 is a light source that emits excitation light in the first wavelength region, and has, for example, a laser light source 31 that emits laser light. A plurality of laser light sources 31 are provided, for example.

14 is a plan view of the light source device 100 shown in FIG. 13B as viewed from above.

The condensing unit 30 includes a light source unit 32 including a plurality of laser light sources 31 and each laser light B1 emitted from the plurality of laser light sources 31 in a predetermined condensing area (or condensing point). A condensing optical system 34 for condensing light to (8) is provided. Further, the condensing unit 30 includes a main frame 33 (see B in FIG. 13) that supports the light source unit 32 and the condensing optical system 34 as one unit.

As shown in FIG. 13B, in the opening 11 of the rear side 7 of the side wall part 2, two light source units 32 are arrange|positioned so that it may line up in the longitudinal direction. Each condensing unit 30 condenses laser light from the plurality of laser light sources 31 onto the fluorescent optical unit 50.

The plurality of laser light sources 31 is, for example, a blue laser light source capable of oscillating blue laser light B1 having a peak wavelength of light emission intensity in a wavelength range of 400 nm or more and 500 nm or less as a first wavelength range. As the laser light source 31, not a light source that emits laser light, but other solid state light sources such as LEDs may be used.

As shown in FIG. 13A, the upper surface portion 4 is disposed above the two condensing units 30. The upper surface portion 4 is connected to the side wall portion 2 and the two condensing units 30. The front portion 3 is connected to the fluorescent optical unit 50, the upper surface portion 4 and the base 1. The lid portion 5 is disposed so as to cover an area between the two condensing units 30 and is connected to the upper surface portion 4.

The method of fixing and connecting the members is not limited. For example, members are engaged with each other through a predetermined engaging portion, and the members are fixed and connected by screwing or the like.

As shown in FIG. 14, the condensing optical system 34 includes an aspherical mirror 35 and a planar mirror 36. The aspherical mirror 35 reflects the emitted light from the plurality of laser light sources 31 and condenses it onto the planar mirror 36. The planar mirror 36 reflects the reflected emission light so that the emission light reflected by the aspherical mirror 35 is condensed on the predetermined condensing area 8 as described above. As described later, the condensing area 8 is disposed on the phosphor layer 53 of the phosphor unit included in the fluorescence optical unit 50.

On the other hand, the main frame 33 described above supports the light source unit 32, the aspherical mirror 35, and the flat mirror 36 as one unit.

The fluorescent optical unit 50 may be provided with a phosphor unit and a fluorescent light collimator lens.

The phosphor unit includes, for example, a transparent substrate that is a rotating plate in a disk shape, a motor as a driving unit for rotating the transparent substrate, and the first to sixth implementations related to the present technology, for example, installed on one side of the transparent substrate. You may include the light emitting element of at least one embodiment among the forms. The transparent substrate may function as a support for supporting the light emitting element. The motor and the transparent substrate function as a moving mechanism for moving the light emitting element over time. Due to the movement mechanism, the irradiation position of the excitation light with respect to the light-emitting element moves over time, so that unexcited phosphor atoms are sequentially arranged at the irradiation position of the excitation light, and the light-emitting element can emit light efficiently .

<9. Eighth embodiment (projector example)>

The projector of the eighth embodiment (projector example) according to the present technology includes a light source device according to the seventh embodiment according to the present technology, an image generation unit that generates an image using light emitted from the light source device, And a projection unit that projects an image generated by the image generating unit.

15 is a schematic diagram showing a configuration example of a projector according to an eighth embodiment according to the present technology.

The projector 400 includes a light source device 100, an image generating unit 200 that generates an image using light emitted from the light source device 100, and image light generated by the image generating unit 200. It is provided with a projection unit 300 to project.

The image generating unit 200 includes an integrator element 210, a polarization conversion element 215, a condensing lens 216, a dichroic mirror 220 and 222, a mirror 226, 227 and 228, and relay lenses 250 and 260. Further, the image generating unit 200 includes a field lens 230 (230R, 230G and 230B), a liquid crystal light valve 240R, 240G and 240B, and a dichroic prism 270 ).

The integrator element 210 as a whole has a function of arranging incident light irradiated from the light source device 100 to the liquid crystal light valves 240R, 240G and 240B in a uniform luminance distribution. For example, the integrator element 210 includes a first fly-eye lens 211 having a plurality of microlenses, not shown, arranged in two dimensions, and one for each microlens. It includes a second fly-eye lens 212 having a plurality of microlenses arranged to correspond.

The parallel light incident from the light source device 100 to the integrator element 210 is divided into a plurality of beams by the microlenses of the first fly-eye lens 211, and in the second fly-eye lens 212 Each image is formed on the corresponding microlenses. Each of the microlenses of the second fly's eye lens 212 functions as a secondary light source and irradiates a plurality of parallel light onto the polarization conversion element 215 as incident light.

The polarization conversion element 215 has a function of aligning the polarization state of incident light incident through the integrator element 210 or the like. The polarization conversion element 215 emits blue light (B3), green light (G3), and red light (R3) through, for example, a condensing lens 216 disposed on the emission side of the light source device 100 Emits light.

The dichroic mirrors 220 and 222 have a property of selectively reflecting color light in a predetermined wavelength region and transmitting light in a wavelength region other than that. For example, the dichroic mirror 220 selectively reflects the red light R3. The dichroic mirror 222 selectively reflects the green light G3 of the green light G3 and the blue light B3 transmitted through the dichroic mirror 220. The remaining blue light B3 passes through the dichroic mirror 222. Accordingly, the light emitted from the light source device 100 is separated into a plurality of color lights of different colors.

The separated red light R3 is reflected by the mirror 226 and parallelized by passing through the field lens 230R, and then incident on the liquid crystal light valve 240R for modulating red light. The green light G3 is parallelized by passing through the field lens 230G, and then enters into the liquid crystal light valve 240G for modulating green light. The blue light B3 is reflected by the mirror 227 through the relay lens 250 and further reflected by the mirror 228 through the relay lens 260. The blue light B3 reflected by the mirror 228 is parallelized by passing through the field lens 230B, and then enters the liquid crystal light valve 240B for modulating blue light.

The liquid crystal light valves 240R, 240G, and 240B are electrically connected to an unillustrated signal source (eg, a personal computer) that supplies an image signal including image information. The liquid crystal light valves 240R, 240G, and 240B modulate incident light for each pixel based on the image signal of each color supplied, and generate a red image, a green image, and a blue image, respectively. The modulated light of each color (formed image) is incident on the dichroic prism 270 and synthesized. The dichroic prism 270 combines the light of each color incident from the three directions by overlapping each other, and emits it toward the projection unit 300.

The projection unit 300 has a plurality of 310 or the like, and irradiates the light synthesized by the dichroic prism 270 onto a screen (not shown). Thereby, a full-color image is displayed.

By appropriately setting the shape and the like of the light source device 100, it becomes possible to improve the design of the external appearance of the projector 400 and the like.

On the other hand, the embodiments related to the present technology are not limited to the respective embodiments described above, and various modifications can be made without departing from the gist of the present technology.

In addition, the effect described in this specification is an illustration to the last, and is not limited, Further, another effect may exist.

In addition, the present technology can also have the following configuration.

[One]

At least a phosphor layer and an emission angle selection layer for emitting light incident at a predetermined angle,

The phosphor layer includes a phosphor and a light scattering material,

The light emitting element, wherein the phosphor layer and the emission angle selection layer are arranged in this order.

[2]

Further comprising a reflective layer,

The light emitting element according to [1], wherein the reflective layer, the phosphor layer, and the emission angle selection layer are arranged in this order.

[3]

Further comprising a dielectric spacer,

The light emitting element according to [2], wherein the dielectric spacer is disposed between the reflective layer and the phosphor layer.

[4]

The light-emitting device according to [3], wherein the dielectric spacer has a dielectric constant of 2.5 to 6.0 in a region of a wavelength of 380 nm to 780 nm, and a thickness of 10 nm to 400 nm.

[5]

The phosphor layer further comprises metal nanoparticles,

The light-emitting device according to any one of [1] to [4], wherein the metal nanoparticles are disposed on the surface of the phosphor.

[6]

Further comprising a reflective layer,

The light-emitting element according to [5], wherein the reflective layer, the phosphor layer, and the emission angle selection layer are arranged in this order.

[7]

Further comprising a dielectric spacer,

The light emitting device according to [6], wherein the dielectric spacer is disposed between the reflective layer and the phosphor layer.

[8]

The light-emitting element according to [7], wherein the dielectric spacer has a dielectric constant of 2.5 to 6.0 in a region of a wavelength of 380 nm to 780 nm, and a thickness of 10 nm to 400 nm.

[9]

The light emitting device according to any one of [1] to [8], wherein the phosphor is a low reabsorption phosphor.

[10]

The light emitting device according to any one of [1] to [9], wherein the emission angle selection layer is formed of a dielectric film.

[11]

The light emitting element according to any one of [1] to [10], wherein the emission angle selection layer has a lattice structure.

[12]

The light emitting element according to any one of [1] to [10], wherein the emission angle selection layer has a patch structure.

[13]

The light-emitting element according to any one of [1] to [12], wherein the light scattering body is a light scattering reflector.

[14]

The light-emitting element according to any one of [1] to [12], wherein the light scattering body is a scattering particle.

[15]

The light-emitting element according to any one of [1] to [12], wherein the light scattering body is a void.

[16]

A light source device comprising the light-emitting element according to any one of [1] to [15], a light source that emits excitation light, and a moving mechanism that moves the irradiation position of the excitation light to the light-emitting element over time.

[17]

The light source device according to [16], and

An image generating unit that generates an image using light emitted from the light source device;

A projector comprising a projection unit that projects an image generated by the image generating unit.

1000 (1000-1 ∼ 1000-10): Light-emitting element
1001, 1006, 1007: emission angle selection layer
1002: phosphor layer
1003: reflective layer
1004: dielectric spacer
1005: light scattering reflector (light scattering body)
500: phosphor
600: light scatterer
700: metal nanoparticles

Claims (17)

At least a phosphor layer and an emission angle selection layer for emitting light incident at a predetermined angle,
The phosphor layer includes a phosphor and a light scattering material,
The light emitting element, wherein the phosphor layer and the emission angle selection layer are arranged in this order. The method of claim 1,
Further comprising a reflective layer,
The light-emitting element, wherein the reflective layer, the phosphor layer, and the emission angle selection layer are arranged in this order. The method of claim 2,
Further comprising a dielectric spacer,
The light-emitting element, wherein the dielectric spacer is disposed between the reflective layer and the phosphor layer. The method of claim 3,
The light-emitting element, wherein the dielectric spacer has a dielectric constant of 2.5 to 6.0 in a region of a wavelength of 380 nm to 780 nm and a thickness of 10 nm to 400 nm. The method of claim 1,
The phosphor layer further comprises metal nanoparticles,
The light emitting device, wherein the metal nanoparticles are disposed on the surface of the phosphor. The method of claim 5,
Further comprising a reflective layer,
The light-emitting element, wherein the reflective layer, the phosphor layer, and the emission angle selection layer are arranged in this order. The method of claim 6,
Further comprising a dielectric spacer,
The light-emitting element, wherein the dielectric spacer is disposed between the reflective layer and the phosphor layer. The method of claim 7,
The light-emitting element, wherein the dielectric spacer has a dielectric constant of 2.5 to 6.0 in a region of a wavelength of 380 nm to 780 nm and a thickness of 10 nm to 400 nm. The method of claim 1,
The light emitting device, wherein the phosphor is a low reabsorption phosphor. The method of claim 1,
The light emitting device, wherein the emission angle selection layer is formed of a dielectric film. The method of claim 1,
The light emitting device, wherein the emission angle selection layer has a lattice structure. The method of claim 1,
The light emitting device, wherein the emission angle selection layer has a patch structure. The method of claim 1,
The light-emitting device, wherein the light scattering body is a light-scattering reflector. The method of claim 1,
The light-emitting device, wherein the light scattering body is a scattering particle. The method of claim 1,
The light-emitting element, wherein the light scattering body is a void. A light source device comprising the light-emitting element according to claim 1, a light source for emitting excitation light, and a movement mechanism for moving the irradiation position of the excitation light to the light-emitting element over time. The light source device according to claim 16,
An image generating unit that generates an image using light emitted from the light source device;
A projector comprising a projection unit that projects an image generated by the image generating unit.

Images